本文提出了金属材料的一种近似线性化初始屈服函数，它是位在Tresca六边形和双剪应力六边形之间的十二边形（族）。
A set of approximate linearized yield-functions is presented for metal materials . It is a set of polygons with twelve edges which locates between the Tresca 's hexagon and the twin shear-stress-hexagon .
十二边形